Macroscopic quantum mechanics: theory and experimental concepts of optomechanics

Rapid experimental progress has recently allowed the use of light to prepare\nmacroscopic mechanical objects into nearly pure quantum states. This research\nfield of quantum optomechanics opens new doors toward testing quantum\nmechanics, and possibly other laws of physics, in new regimes. In the first\npart of this paper, I will review a set of techniques of quantum measurement\ntheory that are often used to analyze quantum optomechanical systems. Some of\nthese techniques were originally designed to analyze how a classical driving\nforce passes through a quantum system, and can eventually be detected with\noptimal signal-to-noise ratio --- while others focus more on the quantum state\nevolution of a mechanical object under continuous monitoring. In the second\npart of this paper, I will review a set of experimental concepts that will\ndemonstrate quantum mechanical behavior of macroscopic objects --- quantum\nentanglement, quantum teleportation, and the quantum Zeno effect. Taking the\ninterplay between gravity and quantum mechanics as an example, I will review a\nset of speculations on how quantum mechanics can be modified for macroscopic\nobjects, and how these speculations --- and their generalizations --- might be\ntested by optomechanics.\n